Lightweight Design Of Articulated Electric Bus Body Frame

Articulated buses have more passenger capacity than traditional buses.The research object of this paper is a pure electric articulated urban bus developed by a company.The whole vehicle is driven by power battery.This kind of bus that replaces traditional fuel with electric energy has the advantages of low pollution and low noise,and is the main development direction of urban public transportation today.Lightweight design of the bus body frame can effectively reduce the weight of the vehicle,extend the cruising range and optimize vehicle performance.In this paper,based on the finite element analysis of the bus body frame,the optimization design was carried out.The main research contents are as follows:(1)According to the 2D drawings and related parameters of articulated bus body skeleton provided by the company,a 3D digital model was established in SolidWorks,and it was directly imported into ANSYS Workbench through transmission interface.In Workbench,the pre-processing of material definition,mid-plane extraction,meshing and load determination was carried out,and the finite element model of body frame with shell and solid hybrid elements was created.(2)The static analysis of the finite element model of the body skeleton was carried out.The intensity and rigidity of articulated buses under four working conditions were checked.The analysis results show that the static structure performance of the body skeleton meets the requirements for use.The steel frame connection method of the two positions of the body frame was re-established.The finite element simulation results show that the common node method can replace the welding unit,and the riveting process reduces the strength of the body structure relative to the welding process.(3)The modal analysis of the finite element model of the body skeleton was carried out.Using Block Lanczos numerical solution method,the free modal analysis of the body frame was carried out,and the first 20 natural frequencies and modes were extracted.The analysis results show that the bus has good dynamic characteristics.(4)The response surface optimization design of the body frame was carried out.Taking the skeleton wall thickness as the design variable,the body skeleton was grouped into variables.Through sensitivity analysis of design variables,the number of variables was reduced.The design space was sampled by central composite experimental design method,and the response surface proxy model was constructed by Kriging function method.Screening optimization algorithm was used to find the optimal solution.The weight loss of bus skeleton was 153.1 kg,and the weight loss rate was 5.04%.The static and modal analysis of the optimized body skeleton was carried out again.The results show that the optimized body skeleton structure meets the requirements.In this paper,the structural characteristics of pure electric bus body skeleton were analyzed and a lightweight scheme was put forward,which provides a theoretical basis for the future improvement of the enterprise.